Additives for cement to increase the fluidity of cement paste, mortars and concretes have been known and in use for many years. These additives are also known as water reducers because they allow less water to be used in a mortar or concrete without loss of slump (a measure of consistency or workability). This class of cement additives permits the use of less water to obtain the same slump, or the attainment of a higher slump at a given water content, or the use of less portland cement to realize the same compressive strength. The performance requirements for water reducing admixtures are specified in ASTM Method C494-92, "Standard Specifications for Chemical Admixtures for Concrete."
In ASTM C494-92, a water reducing admixture is defined as an admixture that reduces the quantity of mixing water required to produce concrete of a given consistency by at least 5%.
A high range water reducing admixture, also known as a superplasticizer, reduces the quantity of mixing water required to produce concrete of a given consistency by 12% or greater. Commercial water reducing admixtures include lignin sulfonates and naphthalene sulfonate-formaldehyde condensates. More recently, new classes of flow enhancers or water reducers have been described. U.S. Pat. No. 4,814,014 describes a cement composition containing a graft co-polymer containing a polymeric backbone moiety and polymeric side chain moieties wherein one of the polymeric moieties is a polyether moiety and the other is a non-polyether formed by polymerization of ethylenically unsaturated monomers. U.S. Pat. No. 4,808,641 describes a copolymer said to be useful for the purpose of increasing the flowability of fresh concrete which is prepared by copolymerizing (a) 10 to 95 parts by weight of a compound of general formula ##STR1## wherein R.sup.1 is hydrogen or methyl, R.sup.2 is a C.sub.2 -C.sub.4 alkylene, R.sup.3 is hydrogen or a C.sub.1 -C.sub.5 alkyl and e is an integer of 1 to 100 and (b) 5 to 90 parts by weight of a compound of general formula ##STR2## wherein R.sup.4 is hydrogen or methyl or a salt thereof. Similar copolymers are also taught in Japanese Patent Publication (Kokoku) No. 59-18338/1984, U.S. Pat. Nos. 4,972,025, 5,661,206, 5,674,316, and 5,707,445. None of these patents provide any detailed description as to how one might synthesize the copolymer component corresponding to compound (a) above when R.sup.3 is hydrogen (i.e., when the compound has a terminal hydroxyl group).
It would be desirable to prepare better defined reactive unsaturation-containing species which can be used to prepare a wide variety of copolymers useful as superplasticizers and water reducers in cementitious compositions.